Trimming mechanism for formed rotary grinders



June"4 1946.

-L J. GRUENBERG TR-IMMING lMECHA'NISM F-R FORMED )ROTARY GRINDERS vild Nov. l5, 1943 5 Sheets-Sheet l INVENron lvoR J. GRUENBERG N #Mmmm ATTORNE June 4,1946 1 l. J. GRUENBERG l 2,401,552

TRIMMINGMECHANISM FOR FoRM'ED RTARY GRINDERS FifledNOV. 13, 1943 5 Sheets-Sheet 2 'Im/ENTOR. avon J. GRUENBERG w BY ATTO R NEYS June 4, rH946. 1. J. GRUENERG TRIMMING MECHANISM FOR FORMED ROTARY GRINDERS Fild Nov. 13, 1943 5 Sheets-Sheet 3 vlll ATToRNgYg lJune 4, 1946. J. GRUENBERG `TRIM'MING MECHANISM FOR FORMED ROTARY `GIRINDERSl File@ Nova'. 15, 1943 [5 sheets-sheet 4 INVENToR. Non J. GRUENBERG ATTORNEYS' June4, 1946- Y l. J. GRUENBERG TRIMMING MECHANISM FQR FORMED ROTARY GRINDERS Filed NOV. 13, 1943 -5 Sheets-Sheet 5 INVENTQR. von .1. GRUENBERG Y ATTORNEYS Patented June 1946 TG MCHANISM FOR FORMED ROTARY GRINDERS Ivor J. Gruenberg, Pleasant Ridge, Mich., assignor to The Gear Grinding Machine Company, Hamtramck, Mich., a corporation of Michigan application November is. m3. serial No. 510,170

NT orFlcE The invention relates to mechanism for trimm ming or dressing grinder-wheels and more particularly to aconstruction adapted to trim rotary .grinders for the grinding of helicoidal surfaces such as helical gears or the like.

It is a primary object of the invention to -obtain a construction of trimming mechanism which Will develop in a grinder wheel the exact form required for grinding a predetermlned'helicoidal surface. l n Y It is a further object to control said mechanism by a pattern corresponding to a predetermined cross sectional contour of the finished work.

Withthese objects in view, the invention Aconsists, first.l ina trimming mechanism in which a compound movement ,is imparted to a trimming `point in relation to the grinder Wheelv to have any abrading action thereon such as would be performed by an abrading surface coincident c citant. (ci. ist-rui Fig. l is' a diagram illustrating a helical member to be ground, a grinder wheel in operative relation thereto and the plane in which said grinder wheel is trimmed:

Figs.' 2 and 3 are cross sections respectively through portions of male and female coniugate members having helical engagement with each other;

Fig. 4 is a longitudinal sectional elevation of lo the trimming mechanism for the female member;

with the finished surface of the -work in its nieve-4 ment in relation to the grinder wheel duriner the grinding operation.

The invention further consists in a' trimming mechanism in which a vcompound movement,l -is imparted tothe trimming point including a movel ment in a plane through a pattern correspond ing to a predetermined cross sectional contour of the finished work.

The invention further consists in a trimming mechanism including means for constraining 'movement ofthe trimming point to a pattern corresponding to a cross sectional contour of the finished Work together with .means for moving said constraining means through a helical path.

The invention further consists in a "trimming mechanism which is mounted on a reciprocatory Work-holding table of a. grinding machine in' axial alignment with the work thereon so as to be movable through the same path, said'me'chanism Valso including means/constraining the trimming point to movev throughs. path in the plane of rotation correspondliig to the cross sec; tional contour of the work such plane.

The invention further consists in the specific construction of the constraining means through which. the pattern is developed corresponding to the desired cross sectional contouriin the work.

The inventionfurther consists. in various features o! construction as hereinafter set forth.

In the drawings the construction specifically illustrated is designed for trimming arcuate and cycloidal contours. However, the invention is Valso applicable to the trimming o f other contours in grinder wheels for grinding helicoidal mein- Fig. 5 is a similar view of the trimming mechanism forthe male member;` y

Fig. 6 is an end elevation ofV Fig. 4; n

Fig. 7 is an end elevation of Fig. yand Fig. 8 is a plan view showing the trimmer mechanism mounted on the work lholding centers of a grinding machine;

Fig. 9 is a diagram of the ,'l'illustrating the operation of the same;

Fig. 10 is a bottom plan view showing the en- .gagement between the trimming member and carrier;

adjustment. d y

2s The specific work to be ground illustrated in Figs. 1 to 3 comprises a pair of coniugate helicoidal members of the following construction. The male member A has a plurality of projecting an arcuate portion between the points I and 2 and a tangent cycloidal portion between the points 2 and 3. -On the opposite side there is a cycloidal portion between the points I and 4. The female member B shown in Fig. 3 has an arcuate portion between the points 5 and 64 and acycloidal portion between the points 8 and 1. The cycloidal curves `are based on the pitch circles of the respective members and are traced by trimmingk mechanisms of the following construction.

` C is a frame which is adapted to ble mounted von the reciprocatory work table in'axial alignment with the same centers D and D' which support the work to be ground. Mounted in this 46 frame with its axis coincident` with the centers `D and D' is a stationary shaft E having an'integral head E' secured to the frame IC by bolts E2; The opposite end ofthe shaft E engages a bracket n@ detachebxy .securedto the name. `In f termediate its ends there ls mounted on the shaft E a ge'ar segment F having a pitch radiuscorrespending to the pitch circle of the work. This gear segment is keyed to the shaft so as to be held stationary therewith. G is a housing enclosing the gearpogment F and rotatably mounted on the mechanism of Fig. I

Fig. 11 is a similar view showing a different helical teeth thereon, each of which in the plane of rotation is of a contour having on -one side :monacav shaft E by rollerfbearings.` G', G2., In this housing is a shaft Hirotatably mounted inrollerbearings H?, I-I2 and-having `a head portion H? projecting outside the angular movement of the housing G on the shaft E will cause a rolling of vthe pinion segment F' about the gear segment F. Such rolling movement is resiliently opposed by a helical torsion spring I, the opposite ends of which areattached respectively to the The collar-I is rotatably adjustable on said shaft and is anchored by a pin I3 threaded in the housl fing G and engaging one of a series of notches `I4 in said collar. This permits of placing any desired tension on the spring by rotatably adjusting the collar I'. y

The construction as thus far described is 4the same in both the .trimmers for respectively fashioning the male and female grinder wheels. There is, however, a reversal in the position of l the gear andpinionsegments. Thus, for the housing. fiA pinion segment F" mounted'on the shaft H and Vkeyed thereto' intermeshes with the gear segment F so that any .ber K with respect-to .struction isv :such thatl :when moved fromthe lposition shown in Fig. 7

4 screw Jinthe lugJ'I when contacted by the lug K6 limits the free rocking movement of thememthe handle K` is and in full lines, Fig. `9, in ya counter-'clockwise-direction, there will be the followingsequence of opshaftH and to a collar I. n

"Ks, 'the latterbeing erations.

The handle K5 directly actuates the member K, arm K', diamond holder K2 and diamond point the point of tangencybetween the pitch circles of the gear vwheel F and pinion F. .The move- .ment ofthe member K permits the simultaneous female grindertheradius of the stationarygear is greater than the radius of the pinion, while in the male grinderthe radius of thestationary gear is less than the radius of the pinion. The

same gearsegments may be used inboth constructions, only their positions are reversed with respect to the shafts E and H. Male trimmer y The trimmer which fashions the grinder wheel for grinding'the male helicoidal member is. briefly ldesignated' as?v the male trimmer and vhas in already" described the the head by"anf.e'ccentric 'pinl H5... J'j is .a

' shaft mounted in the carrier .J to be freely revolu- ;thrust roller bearings Jz and J3. K is azdiamond carrier-which is secured to the 'outerendgof-the shaft J and is' provided Vi with an arm`-K"-extending,forward tofthe planef in which-the trimming is to be performed. The holder K2" for Vthe diamond -K is mounted at the rfree endof the; arm K being adjusted, by a' screw K3 andlocked'in adjustedposition'by a setscrew K4.

The. member K has also' connected vvthereto a handle K5 `which extends radiallyoutf ward andrearward into a position for convenient Y. l operation.K; is a lug secured tothe memberK to, extend; inoverlapping relation to a lug J4 on themember J. ,'Agscrew K'l inthe lug Kjforms an adjin L,able stopV forlenga'ging the lug J4 andV movement oi! the member J under'actuation of the torsionspring I (which has been previously tensioned) or, if desired,a second handle K9 secured to the housing G may be grasped by the operator together with the handle. K5. This maintains the screw K'l in contact with the lug so that the members J and K rotate together. However, as the member J is rotatively fixed to theA shaft H and as the pinion F' iixed onsaid l i shaft is in `mesh with the stationarygear F, this will cause the pinion to roll aboutA the gear carrying-the housing-G with-it. The upon the shaftlE housing rotates and travels with the movement of .translationfof the pinion F'-`but the pinion hasy additionalmovement, viz., arotation about v as indicated its own axis.. As a. consequence, there is a relative movement between 4the lpinion F' and the housing G which Vbrings the shoulder-U on saidy pinion into engagement withaa stop screw L prevents further movement of .thepinion and housing G butthe member Kcan still rotateunder `the actuation ofthe handle K u'ntilthelug Ke contacts witnthe screw Js yasgindicated inl 9. rI 'he effect of the niove-` ments just described-15th the diamond point -Ks will trace-a cycloidal .curve during theV period 1 .dotted'lines at 8', Fig.

when the 4members K and *J arefrotating'j toa removable screw 'J is used for connecting the lugs -Ke and Ji together for certain trimming operations. There. is also a second lug J'.' on vthe member lJ which is spaced from the lug J and is on the opposite side of the lug K. J' is an adjustable screwin the lug J" forminga stop for the lug K. A v

The housing G is provided with a number of adjustable screws functioning as stops for limiting theamount of angular movement of the hous. ing G on the shaft E and for positioning it in relation to the gear segments Fand F. One of these screws L is adapted to engage a shoulder L' on the pinion F' and will limit the rocking movement of said pinion in relation to the housing G when the latter rotates in a clockwise direction (Iigs.'7 ands). Another screw 1..3 engages a;

shoulder I l on the pinion F' when the housing rotates in a counter-clockwise direction. The

shown in Fig." 2` between'l In the continued movement ofthe 'memberl K independently ofthe- Fig. 9. Thus,the entire curve`-is' the' samees the points: andi. .By K", L and'L-, the lengths adjustment ofthe screws of the cycloidal and arcuate portions of thecurve may be' varied or,fif desired, thewhole curve can be made cycloidal by connecting the lugs J*v and Ks to each other by a second screw J.

The grinding of the opposite side of the of the male memberl is performed by a separate grinder wheel which is-trimmed by operations similar to those above described. However. inasmuch as the curve isthe cycloid I-l, Fig. `2, the stop screw U must be adjusted outward from the position shown in Fig. 9. This will .permit v a greater angular movement of the housing about the shaft E before the shoulder L3 of the pinion 'F' contacts with the screw L. lWhile the trimmed surfaces of the two grinder wheels both face the same way, they can be used for grinding opposite sides of the tooth by reversing the work end for end on its supporting centers.

Female trimmer The female trimming mechanism is similar to that of the male trimming mechanism above described with the following differences'. First, the positions ofthe gears F and F are reverse, the onevoi larger radius being engaged with the stathe member J. The con-` initially inv alignment Ywith Y in dotted lines at 8. Fig.` 9. This memberl ,J, .the diamantiv by the contact of the screw J8 l centers D and D tionary shaft E while the one of smaller radius is attached to the shaftH. 'I'he member K is exchanged for a similar member Ka having a bent arm Kb whichcarries the diamond `holder and provides clearance forv the trimming movement. A screw L? in the housing G abuts against the shoulder LE on the stationary gear F and the spring I normally holds the parts lin thisposition shown in Fig. 6. A screw L6 on the left' hand side of the housing is adapted to contact with a 'shoulder L7 on the stationary gear after a predetermined movement of said housing in a clockwise direction.l Onthe right-hand side the screw J8 in the lug J'I previously described, forms a. stop for contact with the lug K and limits movement of the member K in a counterclockwise direction. 'I'he diamond point K8 in the position Fig.. 6, is at the point 6 of the curve, Fig. 3. Therefore, movement of the handle Ks in a clockwise direction will cause said point to trace an arcuate curve corresponding to the curve ,5, Fig. 3, On the other hand, movement of the point K8 from the position, Fig. 6, in a counter-clockwise direction will cause said point to trace a cycloidal curve corresponding to the curve 1, Fig. 3. The length of this curve is limited with the lug K" as was the case with the construction` previously described.

Mounting for the trimming mechanism As previously stated, the frame C of the trimming mechanism is mounted on the work holding of a grinding machine, or in axial alignment therewith.v This grinding machine is'designed for the grinding of helical gears or other helicoidal surfaces, but its speciiic construction is not the subject matter of the instant invention. In general, this machine is provided with a reciprocatory work holding table M on which are mounted the head stock N and tail stock O which, respectively, carry the centers D and D. The head stock is provided with a rotary spindle P which is actuated through 'a gear train P' by a transversely extending rack bar P2.' The outer end of this rack bar has a roller P3 which engages an inclined bar Q on astationary. table or frame R. The arrangement is suchthat when the table M is reciprocated, a rotary movement will be simultaneously imparted to the spindle P such as to move the trimming mechanism (or work) through a helical path in relation to the the curve. table M the point K8 would soon pass out of conoscillation another portion of the curve.

grinder wheel S. This wheel is mounted on a stationary portion of the grinding machine and is set at an angle to the axis of D and D' which is substantially the' saine ofthe-helicalV angle ofthe work. Consequently, whenthe table.

6 grinder wheels are trimmed to the contours vrespectively on the right and on the left of the center line.` The portion of the curve to the right, Fig. 2, is trimmed by movement of thehandle K5 in a counter-clockwise direction, Fig. 7. The diamond point K8 starts'from the point 3 on the pitch circle and traces a cycloidal curve between 3 and 2 and then an arcuate curve between 2 and l. The curve on the left, Fig. 2, starts from the point I and is a continuous cycloid to the point I. For grinding the female member, Fig. 3, a single grinder wheel is employed and an arcuate curve is traced between the points 6 and 5 and a, cycloidal curve between the points 5 and 1. 'I'he movement just described would not alone fashion the grinder wheel to a forml which would reproduce these curves in the work. In fact, a grinder wheel trimmed to this contour in any cross sectional plane thereof would cause interference in the grinding operation which would destroyv such contour. However, Whenthetrimming mechanism is mounted as described in the last paragraph and is moved through a helical path while at the same time an oscillatory movement is imparted to the trimming point by the actuation of the handle K.

a form will be generated in the grinder wheel which will grind the work to the desired contour. Before starting the trimming operation, the table M is moved to a position (by manually operable means not shown) where the trimming point Ks is at one end of the curve which it is to trace. As shown in Fig. 8, the grinder wheel to .be trimmed is for grinding the female member, and the trimming point Ks is located at one side of this wheel. It is then oscillated through movement of the handle K to trim a' short length of If vthere were no movement of the tact with the wheel, but if the table is moved slightly Vforward the point will again be brought in contact with the grinder wheel to trim by its action is continued to progressively trim successive portions of the curve until the trimming point arrives, at the end of the curve on the opposite side of the grinder wheel. It would, of course. be possible -to automatically oscillate the handle K5 in timed relation to the movement of the table M and rotation of the trimming mechanism with the spindle P.

n l Summary vMy improved trimming mechanism performs a function in the fashioning of the grinder wheel' which is similar to that which would be performed byan abrasive surface coincident with the iin.-

M.reciprocates, there will beamovementfof the -Y work relative to the grinder Awheel suoli asi-to cause a relative advancement of the latter longitudinally through the helical groove between opposed helicoidal surfaces. When the trimming mechanism is mounted on the centers D and D or other mounting in axial alignment therewith, it Willbe given the same movement as is imparted to the work when on said centers. The spindle P has a head P4 at its forward end which is coupled to the frame C by a pin or dos P5, thereby causing said frame to rotate with the spindle.

Operation f for grinding the specific helicoidal members shown in Figs. 2 and 3, the procedure is as follows: For grinding the male member, Fig. 2, separate ished surfaceof the work in the relative movement of the latter to the grinder wheel. The

form actually imparted to the grinder wheel is not the same in successive trimming operations, for the radius of the wheel is a factor which is involved. However, regardless of the radius of the wheel andthe form imparted thereto, the

grinding of the work will always be the same and will impart the exact cross sectional contour desired.

While I have described my trimming mecha-V nism designed for fashioning grinder wheels, it is obvious that it would be capable of fashioning other `rotary cutting tools, such for instance as milling cutters.

What I claim as my invention is:

1. In a trimming mechanism for rotary tools, the combination with a frame, two arcuate members mounted therein, one fixed thereto and the other constrained to rou about the periphery of the nrst, a trimmer point mounted on the rolling member to move therewith and to trace a cycloidal curve, and a pivot in said last mentioned other constrained"to roll about the periphery ofV the rst, a trimmer'point mounted on said rolling member to move therewith, and a pivot in said last mentioned means permitting the independent rotation of said trimmer point about a different center in alignment with a point of tangency of said arcuate members. A

3. In a trimming mechanism for rotary tools, the combination with a frame, of two arcuate members, one xed to said frame and the other constrained to roll about the first, a trimmer member carrying a trimmer point and mounted on said rolling member to be independently rotatable about an eccentric axis, means for causing said rolling member and trimmer member to move together whereby said trimmer point will trace a cycloidal curve, and means for independently rotating said trimmer member about said eccentric axis to trace an arcuate curve.

4. In a trimming mechanism for rotary tools, l

the combinationwith a frame, of two arcuate members, one ilxed to said frame and the other constrained to roll about the first, a trimmer member mounted on said rolling member to be rotatable about an eccentric axis thereon, cooperating overlapping shoulders on said trimmerv member and rolling member to limitl relative movement thereof vin one direction, resilient means for yieldably holding said shoulders vin contact during a portion of the movement of said trimmer member, and a stop for arresting movement of said rolling member while permitting continued movement of said trimmer member about said eccentric axis.

5. A trimmer member for rotary tools comprising a frame adapted for axial and rotative reciprocation, a, shaft rigidlyv mountedin said frame concentric lwith the axis thereof, a gear segment xed on said shaft, a second frame pivotally mounted on said shaft, a second shaft journalied in said second frame, a gear segment fixed on said second shaft inV mesh with and rollable about said first gear segment, a carrier mounted and vilxled upon said second shaft, a pivot mounted on` said carrier with its axis in alignment 'with the pitch circle of said rollable gear segment, a trimmer member mounted on said pivot, opposed overlapping shoulders on said carrier and trimmer, resilient means for yieldabiy holding said *shoulders in contact whereby said carrier member and trimmer member move together, an adjustablev stop for limiting movement of said carrier, and a second adjustable stop for limiting the independent rotation of said trimmer.

6. A trimming mechanism for rotary tools comprising a frame adapted for axial and rotative reciprocation. a shaft rigidly mounted in said frame concentricwith the axis thereof, a gear segment fixed on said shaft, a second frame pivotally mounted on said shaft, a second Shaft journalled in said second frame, a gear segment fixed on said `second shaft in mesh with and rollv able about said rst gear segment, a carrier mounted and xed upon said second shaft,- a pi'vot mounted in said carrier with its axis in alignment with a pitch circle of said rotatable gear segment, a trimmer member mounted on saidv pivot, relatively adjustable opposed overlapping shoulders on said carrier and trimmer, means for applying resilient torque to said second shaftto yieldably press the Ashoulder on said carrier against the shoulder on said trimmer, a,handle on said trimmer member for manually rotating the same.

IVOR J. GRU'ENBERG. 

